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\multicolumn{2}{|c|}{\LARGE\bf THE\hspace*{1cm}STAR\hspace*{1cm}FORMATION\hspace*{1cm}NEWSLETTER} \\ [0.3cm]
\multicolumn{2}{|c|}{\large\em An electronic publication dedicated to early stellar evolution and molecular clouds} \\ [0.3cm]
{\hspace*{0.8cm} No. 103 --- 8 May 2001 } & \multicolumn{1}{r|}{Editor: Bo Reipurth (reipurth@casa.colorado.edu)\hspace*{0.8cm}} \\ [-0.1cm]
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%{\Large\em From the Editor}
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{\Large\em Abstracts of recently accepted papers}
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%% Between these brackets you write the title of your paper:
{\large\bf{Chemically active outflow L\,1157}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{R. Bachiller, M. P\'{e}rez Guti\'{e}rrez, M. S. N.
Kumar and M. Tafalla}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{IGN Observatorio Astron\'{o}mico Nacional, Apartado 1143,
E-28800 Alcal\'{a} de Henares, Spain}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: bachiller@oan.es}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We present millimeter-wave maps of the L\,1157 bipolar
outflow in several molecular emission lines. The CO
emission traces the bulk of the outflowing gas in the red
and blue shifted lobes displaying a remarkable S-shaped
symmetry indicating the presence of a precessing jet. We
determine the physical characteristics of the CO flow and
show evidence for 3 or 4 independent episodes of mass
ejection from the source. Molecules such as C$_3$H$_2$,
N$_2$H$^+$ and DCO$^+$ are seen to be abundant only in the
quiescent medium, and result to be the best tracers of the
high-density core surrounding the driving source of the
outflow. Other molecules (SiO, CH$_3$OH,H$_2$CO, HCN, CN,
SO, SO$_2$) are abundant in the outflow lobes, but exhibit
strong emission gradients. Multiline observations of some
species indicate that these gradients are not simply due to
excitation effects, but are caused by an actual
stratification in the chemical composition of the shocked
molecular gas. Shock tracers such as SiO, CH$_3$OH, and
sulphur-bearing molecules result to be the most promising
candidates as potential chemical clocks to study the
evolution of outflows. The characteristics of the L\,1157
outflow, when compared to those of other outflows from
Class\,0 sources, indicate that L\,1157 is the prototype
of a category of bipolar outflows around Class\,0
protostars which we denominate ``chemically active
outflows''.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy \& Astrophysics }
%% If preprints are available on the WWW you can give the web
%% direction here.
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{A turbulent MHD
model for molecular clouds and a new method of accretion
on to star-forming cores}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ D. Balsara$^1$, D. Ward-Thompson$^2$, R. M. Crutcher$^{1,3}$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1${NCSA, University of Ilinois, Champaign-Urbana, Illinois, USA} \\
$^2${Dept of Physics and Astronomy, Cardiff University,
PO Box 913, Cardiff CF2 3YB, UK} \\
$^3${Dept of Astronomy, University of Ilinois, Champaign-Urbana,
Illinois, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: spxdw@astro.cf.ac.uk}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
We describe the results of a sequence of simulations of gravitational collapse
in a turbulent magnetized region.
The parameters are chosen to be representative of molecular cloud material.
We find that several protostellar cores and
filamentary structures of higher than average density form. The filaments
inter-connect the high density cores. Furthermore, the magnetic field
strengths are found to correlate positively with the density, in agreement with
recent observations. We make synthetic channel maps
of the simulations and show that material accreting onto the
cores is channelled along the magnetized filamentary structures. This is
compared with recent observations of S106, and shown to be consistent
with these data. We postulate that this mechanism of accretion along
filaments may provide a means for molecular cloud cores to grow to the
point where they become gravitationally unstable and collapse
to form stars.}
% Here you write which journal accepted your paper, for example:
{ Accepted by MNRAS }
%% If preprints are available on the WWW you can give the web
%% direction here.
http://www.astro.cf.ac.uk/pub/Derek.Ward-Thompson/publications.html
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The Historical Variability of T Tau, RY Tau and RW Aur}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Tracy L. Beck and M. Simon}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Department of Physics \& Astronomy, SUNY Stony Brook, Stony Brook,
NY 11794-3800, USA}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: tracy@hilo.ess.sunysb.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We present the historical light curve of T Tau derived from
photographic plates in the Harvard College Observatory archives. We
find that the optical light of T Tau varied by 2-3 (or more) magnitudes
on time scales as short as a month prior to $\sim$ 1917, consistent with
the results of Lozinskii (1949). Extreme light fluctuations of greater
than 2 magnitudes abruptly ceased in the late 1910's and, to the best of
our knowledge, have not repeated since this time. We compare the
observed light variations of T Tau to the T Tauri stars RY Tau and RW
Aur, whose light curves we also constructed from inspection of the
archival plates. We find that variable extinction along the line of
sight to the star is the most likely explanation for the observed light
fluctuation of T Tau during the early part of the 20th century.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
{preprint address: http://www.ess.sunysb.edu/tracy/preprint.html}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Formation of massive stars by growing accretion rate}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ R.~Behrend and A.~Maeder}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Geneva Observatory, CH-1290 Sauverny, Switzerland}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: raoul.behrend@obs.unige.ch}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
We perform calculations of pre-main sequence evolution
of stars from $1$ to $85\,M_{\odot}$ with growing accretion rates
$\dot{M}$. The values of $\dot{M}$
are taken equal to a constant fraction $\tilde{f}$ of the rates of
the mass outflows observed by Churchwell (1998) and Henning
(2000). The evolution of the various stellar parameters is
given, as well as the evolution of the disc luminosity;
electronic tables are provided as a supplement to the articles.
Typically, the
duration of the accretion phase of massive stars is
$\simeq 3 \cdot 10^5\,\mathrm{yr}$. and there is less than $10\%$
difference in the time necessary to form a $8$ or $80\,M_{\odot}$ star.
If in a young cluster all the proto--stellar cores start to
accrete at the same time, we then have a relation $M(t)$
between the masses of the new stars and the time $t$ of their
appearance. Since we also know the distribution of stellar masses at the
end of star
formation (IMF), we can derive the star formation history
$N(t)$. Interestingly enough, the current IMF implies two
peaks of star formation: low mass stars form first and high mass
star form later.}
% Here you write which journal accepted your paper, for example:
{ Accepted by A\&A}
%% If preprints are available on the WWW you can give the web
%% direction here.
http://babbage.sissa.it/abs/astro-ph/0105054
\vspace{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{IRAS 11590--6452 in BHR~71 -- a binary protostellar system?
}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Tyler L. Bourke$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street MS
42, Cambridge MA 02138, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: tbourke@cfa.harvard.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand{\uco}[1]{\mbox{$^{#1}$CO}} % ie \uco{13}\ -> 13co
\newcommand{\jj}[2]{\mbox{$J = #1 \rightarrow #2$}}
\newcommand{\hh}{\mbox{H$_2$}}
\newcommand{\micron}{\mbox{$\mu$m}} % micron
%% Within the following brackets you place your text:
{New AAT near-infrared and SEST \uco{12}\ \jj{2}{1}\ observations are combined
with existing ISO mid-infrared and ATCA cm radio continuum observations to
examine the protostellar content of the Bok globule BHR~71. Together
with observations of Herbig-Haro objects, these data show:
(1) Two protostellar sources, IRS1 and IRS2, with a separation of
$\sim$17$''$ (3400 AU) are located within BHR~71.
(2) Each protostar is driving its own molecular outflow. The outflow from
IRS1 is much larger in extent, is more massive, and dominates the CO emission.
(3) Both protostars are associated with Herbig-Haro objects and shock
excited 2.122 \micron\ \hh\ $v$=1-0S(1) emission, which coincide spatially
with their CO outflows.
(4) IRS1 is associated with cm continuum emission, with a flat or rising
spectrum which is consistent with free-free emission, a signpost of
protostellar origin.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap.J. Letters }
%% If preprints are available on the WWW you can give the web
%% direction here.
{preprints available at:\\
{\tt http://cfa-www.harvard.edu/sfgroup/ } (CfA Star Formation/ISM www
page)\\
{\tt http://cfa-www.harvard.edu/$\sim$bourke/ }}
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{Temperature effects on the 15-85-$\mu$m Spectra of Olivines and Pyroxenes}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ J. E. Bowey$^{1,2}$, C. Lee$^{1}$, C. Tucker$^{1}$,
A. M. Hofmeister$^{3}$, P. A. R. Ade$^{1}$ and M. J. Barlow$^2$
}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Dept. of Physics, Queen Mary, University of London, Mile End Road,
London, E1 4NS, UK.}\\
$^2$ {Dept. of Physics \& Astronomy, University
College London, Gower Street, London, WC1E 6BT, UK}\\
$^3${Dept. Earth $\&$ Planet. Sci., Washington
University, 1 Brookings Dr., St Louis, MO 63110, USA}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact:jeb@star.ucl.ac.uk}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Far-infrared spectra of laboratory silicates are normally obtained at
room temperature even though the grains responsible for astronomical
silicate emission bands seen at wavelengths $>20~\mu$m are likely to
be at temperatures below $\sim 150$~K. In order to investigate the
effect of temperature on silicate spectra, we have obtained absorption
spectra of powdered forsterite and olivine, along with two
orthoenstatites and diopside clinopyroxene, at 3.5$\pm0.5$~K and at
room temperature (295$\pm2$~K). To determine the changes in the
spectra the resolution must be increased from $\sim 1$ to
0.25~cm$^{-1}$ at both temperatures since a reduction in temperature
reduces the phonon density, thereby reducing the width of the infrared
peaks. Several bands observed at 295~K split at 3.5~K. At 3.5~K the
widths of isolated single bands in olivine, enstatites and diopside
are $\sim 90\%$ of their 295~K-widths. However, in forsterite the
3.5-K--widths of the 31-, 49- and 69-$\mu$m bands are, respectively,
90\%, 45\% and 31\% of their 295~K widths. Due to an increase in
phonon energy as the lattice contracts, 3.5-K--singlet peaks occur at
shorter wavelengths than do the corresponding 295-K peaks; the
magnitude of the wavelength shift increases from $\sim 0-0.2~\mu$m at
25~$\mu$m to $\sim 0.9~\mu$m at 80~$\mu$m. In olivines and enstatites
the wavelength shifts can be approximated by polynomials of the form
$ax+bx^2$ where $x=\lambda_{pk}(295$~K$)$ and the coefficients $a$ and
$b$ differ between minerals; for diopside this formula gives a lower
limit to the shift. Changes in the relative absorbances of spectral
peaks are also observed. The temperature dependence of $\lambda_{pk}$
and bandwidth shows promise as a means to deduce characteristic
temperatures of mineralogically distinct grain populations. In
addition, the observed changes in band strength with temperature will
affect estimates of grain masses and relative mineral abundances
inferred using room-temperature laboratory data. Spectral
measurements of a variety of minerals at a range of temperatures are
required to fully quantify these effects.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by MNRAS }
%% If preprints are available on the WWW you can give the web
%% direction here.
http://arXiv.org/abs/astro-ph/0103297
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{HST/NICMOS detection of a partially embedded, intermediate-mass
pre-main-sequence population in the 30 Doradus Nebula
}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Wolfgang Brandner$^1$, Eva K. Grebel$^2$, Rodolfo H.\ Barba$^3$,
Nolan R. Walborn$^4$ \ and Andrea Moneti$^5$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {European Southern Observatory, Karl-Schwarzschild-Str.\ 2, D-85748 Garching, Germany} \\
$^2$ {Max-Planck-Institut f\"ur Astronomie, Am K\"onigstuhl 17, D-69117
Heidelberg, Germany} \\
$^3$ {Facultad de Ciencias Astron\'omicas y Geof\'{\i}sicas, Universidad
Nacional de la Plata, Paseo del Bosque S/N, 1900 La Plata, Argentina}\\
$^4$ {Space Telescope Science Institute, 3700 San Martin Drive, Baltimore,
MD 21218, USA}\\
$^5$ {Institut d'Astrophysique Paris, 98bis Blvd Arago, F-75014 Paris, France}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: wbrandne@eso.org}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We present the detection of an intermediate-mass pre-main-sequence population
embedded in the nebular filaments surrounding the 30 Doradus region in the
Large Magellanic Cloud (LMC) using HST/NICMOS. In addition to four previously
known luminous Class I infrared ``protostars,'' the NICMOS data reveal 20 new
sources with intrinsic infrared excess similar to Galactic pre-main sequence
stars. Based on their infrared brightness, these objects can be identified as
the LMC equivalent of Galactic pre-main sequence stars. The faintest LMC Young
Stellar Objects in the sample have colors similar to T Tauri and have about the
same brightness as T Tauri if placed at the distance of the LMC. We find no
evidence for a lower-mass cut-off in the initial mass function. Instead, the
whole spectrum of stellar masses from pre-main sequence stars with
$\approx$1.5\,M$_\odot$ to
massive O stars still embedded in dense knots appears to be present in the
nebular filaments. The majority of the young stellar objects can be found to
the north of the central starburst cluster R136. This region is very likely
evolving into an OB association.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J., August 2001 issue }
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprints available at
http://arxiv.org/abs/astro-ph/0104274
\v5
{\large\bf{Spectroscopic Diagnostics of Organic Chemistry in the
Protostellar Environment}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{S.B. Charnley$^{1}$, P. Ehrenfreund$^{2}$ \& Y-J. Kuan$^{3}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Space Science Division, MS 245--3, NASA Ames Research Center,
Moffett Field, CA 94035, U.S.A.}\\
$^{2}$ {Raymond and Beverly Sackler, Laboratory for Astrophysics,
at Leiden Observatory, P O Box 9513, 2300 RA Leiden, The
Netherlands}\\
$^{3}$ {Department of Earth Sciences, National Taiwan Normal
University, Taipei, Taiwan \& Institute of Astronomy and
Astrophysics, Academia Sinica, P.O. Box 1-87, Nankang, Taipei,
Taiwan}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: charnley@dusty.arc.nasa.gov}
%% If you use any personal Latex commands in your abstract, please include
%% their definitions here.
%% Within the following brackets you place your text:
{ A combination of astronomical observations, laboratory studies, and
theoretical modelling is necessary to determine the organic chemistry
of dense molecular clouds. We present spectroscopic evidence for the
composition and evolution of organic molecules in protostellar
environments. The principal reaction pathways to complex molecule
formation by catalysis on dust grains and by reactions in the
interstellar gas are described. Protostellar cores, where warming of
dust has induced evaporation of icy grain mantles, are excellent sites
in which to study the interaction between gas phase and grain-surface
chemistries. We investigate the link between organics that are
observed as direct products of grain surface reactions and those which
are formed by secondary gas phase reactions of evaporated surface
products. Theory predicts observable correlations between specific
interstellar molecules, and also which new organics are viable for
detection. We discuss recent infrared observations obtained with the
{\it Infrared Space Observatory}, laboratory studies of organic
molecules, theories of molecule formation, and summarise recent
radioastronomical searches for various complex molecules such as
ethers, azaheterocyclic compounds, and amino acids.
}
% Here you write which journal accepted your paper, for example:
{Accepted by Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy }
%% If preprints are available on the WWW you can give the web
%% direction here.
{http://www.strw.leidenuniv.nl/$\sim$ pascale/publications.html\#reviews}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Biomolecules in the Interstellar Medium and Comets}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{S. B. Charnley$^1$, S. D. Rodgers$^1$, Y.-J. Kuan$^2$,
H.-C. Huang$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{$^1$Space Science Division, MS 245-3, NASA Ames Research Center,
Moffett Field, CA 94035, U.S.A. \\
$^2$National Taiwan Normal
University \& Academia Sinica Inst.\ of Astron.\ \& Astrophys., P.O. Box
1-87, Nankang, Taipei, Taiwan}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: rodgers@dusty.arc.nasa.gov}
%% If you use any personal Latex commands in your abstract, please include
%% their definitions here.
%% Within the following brackets you place your text:
{We review recent studies of organic molecule formation in dense
molecular clouds and in comets. We summarise the known organic
inventories of molecular clouds and recent comets, particularly
Hale-Bopp. The principal chemical formation pathways involving gas
phase reactions, as well as formation by catalytic reactions on grain
surfaces or through dust fragmentation, are identified for both dense
clouds and cometary comae. The processes leading to organic molecules
with known biological function, carbon chains, deuterium
fractionation, HNC and S-bearing compounds are described.
Observational searches for new interstellar organics are outlined and
the connection between observed interstellar organics and those
detected in comets Hale-Bopp and Hyakutake are discussed.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Advances in Space Research}
%% If preprints are available on the WWW you can give the web
%% direction here.
{http://xxx.lanl.gov/abs/astro-ph/0104416}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{A Two-Step Initial Mass Function:
Consequences of Clustered Star Formation for Binary Propertie}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Richard H. Durisen$^1$, Michael F. Sterzik$^2$ \ and
Brian K. Pickett$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, SW319, Indiana University,
Bloomington, Indiana 47405, U.S.A.} \\
$^2$ {European Southern Observatory, Alonso de Cordova 3107, Vitacura,
Casilla 19001, Santiago 19, Chile} \\
$^2$ {Department of Chemistry and Physics, Purdue University Calumet,
2200 169th Street, Hammond, Indiana 46323, U.S.A.}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: durisen@astro.indiana.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{If stars originate in transient bound clusters of
moderate size, these clusters will decay due to dynamic
interactions in which a hard binary forms and ejects most or
all the other stars. When the cluster members are chosen at
random from a reasonable initial mass function (IMF),
the resulting binary characteristics
do not match current observations. We find a significant
improvement in the trends of binary properties from this
scenario when an additional constraint is taken into account,
namely that there is a distribution of total cluster masses
set by the masses of the cloud cores from which the clusters
form. Two distinct steps then determine final stellar masses --
the choice of a cluster mass and the formation of the individual
stars. We refer to this as a ``two-step'' IMF.
Simple statistical arguments are used in this Paper to show
that a two-step IMF, combined with typical results from dynamic
few-body system decay, tends to give better agreement between
computed binary characteristics and observations than
a one-step mass selection process.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. Astrophys.}
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
{\large\bf{Energetic and thermal processing of interstellar ices}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{P. Ehrenfreund$^{1}$, L. d'Hendecourt$^{2}$, S.B. Charnley$^{3}$, \&
R. Ruiterkamp$^{1}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^{1}$ {Raymond and Beverly Sackler, Laboratory for Astrophysics,
at Leiden Observatory, P O Box 9513, 2300 RA Leiden, The
Netherlands}\\
$^{2}$ {Institut d'Astrophysique Spatiale (CNRS), Astrochimie
Experimentale, Universite Paris XI - B\^atiment 121, 91405 Orsay
Cedex, France}\\
$^3$ {Space Science Division, MS 245--3, NASA Ames Research Center,
Moffett Field, CA 94035, U.S.A.}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: pascale@strw.leidenuniv.nl}
%% If you use any personal Latex commands in your abstract, please include
%% their definitions here.
%% Within the following brackets you place your text:
{ Our current knowledge on the chemical composition of interstellar
ices is summarised with respect to the possible contribution of
energetic photons and particles to their observed state. We describe
the inventory of astronomical ices as determined by infrared
observations from the Infrared Space Observatory ISO and laboratory
spectroscopy. Sources of radiolysis, UV photolysis, and ice heating
are then discussed in the context of the chemical state of material in
dense molecular clouds and in protostellar cores. Through specific
examples we show how energetic processing can explain the observed
solid state characteristics of several key molecules: CH$_3$OH, CO$_2$
and OCN$^-$. We also discuss the gaseous and solid-state
photochemistry of the first organic acid detected in interstellar
ices, HCOOH.
}
% Here you write which journal accepted your paper, for example:
{JGR-Planets, in press }
%% If preprints are available on the WWW you can give the web
%% direction here.
{http://www.strw.leidenuniv.nl/$\sim$ pascale/publications.html\#reviews}
\vspace{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Tracing the Mass during Low-Mass Star Formation.
II. Modelling the Submillimeter Emission from Pre-Protostellar Cores}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Neal J. Evans II$^1$, Jonathan M. C. Rawlings$^2$, Yancy L. Shirley$^1$ \
and Lee G. Mundy$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, The University of Texas at Austin,
Austin, Texas 78712--1083, USA} \\
$^2$ {Department of Physics and Astronomy, University College London, Gower
Street, London WC1E 6BT, UK} \\
$^3$ {Department of Astronomy, University of Maryland, College Park, MD, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: nje@astro.as.utexas.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand{\Td}{\mbox{$T_{d}$}}
%% Within the following brackets you place your text:
{We have modeled the emission from dust in pre-protostellar cores, including a
self-consistent calculation of the temperature distribution
for each input density distribution. Model density distributions include
Bonnor-Ebert spheres and power laws. The Bonnor-Ebert
spheres fit the data well for all three cores we have modeled.
The dust temperatures
decline to very low values ($\Td \sim 7$ K) in the centers of
these cores, strongly affecting the dust emission. Compared to
earlier models that assume constant dust temperatures, our models indicate
higher central densities and smaller regions of relatively constant
density. Indeed, for L1544, a power-law density distribution, similar to that
of a singular, isothermal sphere, cannot be ruled out.
For the three sources modeled herein, there seems to be a sequence of
increasing central condensation, from L1512 to L1689B to L1544.
The two denser cores, L1689B and L1544,
have spectroscopic evidence for contraction, suggesting
an evolutionary sequence for pre-protostellar cores.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophys. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprints available from
{http://peggysue.as.utexas.edu/yshirley/research.html}
or {http://xxx.lanl.gov/abs/astro-ph/0104238}
\clearpage
\newcommand{\ie}{{\it i.e.}}
\newcommand{\eg}{{\it e.g.}}
\newcommand{\cc}{\ifmmode{\,{\rm cm}^{-3}}\else{$\,{\rm cm}^{-3}$}\fi}
\newcommand{\cq}{\ifmmode{\,{\rm cm}^{-2}}\else{$\,{\rm cm}^{-2}$}\fi}
\newcommand{\pc}{\ifmmode{\,{\rm pc}}\else{$\,{\rm pc}$}\fi}
\newcommand{\kms}{\ifmmode{\,{\rm km}\,{\rm s}^{-1}}\else{km s$^{-1}$}\fi}
\newcommand{\kmspc}{\ifmmode{\,{\rm km}\,{\rm s}^{-1}\,{\rm
pc}^{-1}}\else{km s$^{-1}$ pc$^{-1}$}\fi}
\newcommand{\Kkms}{\ifmmode{\,{\rm K\,km\,s}^{-1}}\else{$\,{\rm
K\,km\,s}^{-1}$}\fi}
\newcommand{\twCO}{\ifmmode{\rm ^{12}CO}\else{$\rm ^{12}CO$}\fi}
\newcommand{\thCO}{\ifmmode{\rm ^{13}CO}\else{$\rm ^{13}CO$}\fi}
\newcommand{\CeiO}{\ifmmode{\rm C^{18}O}\else{$\rm C^{18}O$}\fi}
\newcommand{\HH}{\ifmmode{\rm H_2}\else{$\rm H_2$}\fi}
\newcommand{\nHH}{\ifmmode{n_{\rm H_2}}\else{$n_{\rm H_2}$}\fi}
\newcommand{\Jone}{\ifmmode{\rm {(J=1--0)}}\else{{(J=1--0)}}\fi}
\newcommand{\Jtwo}{\ifmmode{\rm {(J=2--1)}}\else{{(J=2--1)}}\fi}
\newcommand{\Jthr}{\ifmmode{\rm{(J=3--2)}}\else{{(J=3--2)}}\fi}
\newcommand{\Jfou}{\ifmmode{\rm{(J=4--3)}}\else{{(J=4--3)}}\fi}
\newcommand{\Jfo}{\ifmmode{\rm{J=4--3}}\else{{J=4--3}}\fi}
\newcommand{\Jon}{\ifmmode{\rm{J=1--0}}\else{{J=1--0}}\fi}
\newcommand{\Jtw}{\ifmmode{\rm{J=2--1}}\else{{J=2--1}}\fi}
\newcommand{\Jth}{\ifmmode{\rm{J=3--2}}\else{{J=3--2}}\fi}
\newcommand{\Av}{\ifmmode{A_V}\else{$T_A$}\fi}
\newcommand{\msol}{\ifmmode{\rm M_\odot}\else{${\rm M}_\odot$}\fi}
{\large{\bf{Filamentary structure and helical magnetic fields in the
environment of a starless dense core}}}
{\bf E. Falgarone$^1$, J. Pety$^2$, and T.G. Phillips$^3$}
$^1${Radioastronomie, Ecole Normale Sup{\'e}rieure,
24 rue Lhomond, 75005 Paris, France}\\
$^2${IRAM, 300 rue de la Piscine, 38406 Saint Martin d'H\`eres, France} \\
$^3${California Institute of Technology, Pasadena, CA 91125, USA}
The environment of L1512, a starless dense core,
has been mapped at high angular resolution in the \twCO\Jtwo\
line over more than 1 pc and a few positions observed in the
\twCO\Jthr\ and \Jfo\ lines. The gas
outside the dense core is structured in several filaments,
roughly 1 pc long and $\sim$ 0.1 pc thick, converging at the dense
core position.
Small longitudinal ($\sim 1 \kmspc$)
but large transverse (up to 8 \kmspc) velocity gradients are observed.
Remarkably, the transverse gradients can be seen to
change sign periodically along at least one of the filaments. Thus, there
are
oscillations in
the toroidal velocity within the filaments which may be a signature
of a magneto-hydrodynamical instability developing in
filaments permeated by a helical magnetic field. In the case of
L1512, according to the analysis of Fiege \& Pudritz (2000),
the growth rate of the instability is low, corresponding to a
timescale of the order of a Myr. We deduce from the wavelength of the
oscillations that the
toroidal component of the magnetic field dominates
the poloidal
component. The toroidal component helps confine the filaments which are
not otherwise confined, either by self-gravity ($m/m_{vir}\sim 0.2$) or by
the
pressure of the galactic HI layer or external turbulent pressure.
We find that the velocity gradients in the vicinity of the dense core
provide an estimate for an upper limit to the
accretion rate onto the dense core of
$\dot{M}=4 \times 10^{-6}$ \msol\ yr$^{-1}$.
For the gas characteristics in the filaments,
we find that a broad range of density and temperature is allowed
for the gas, between
$n_\HH=2\times 10^3$ \cc\ for the coldest case ($T_k=20$ K)
down to $n_\HH=180$ \cc\ for the warmest ($T_k=250$ K).
{Accepted by Astron. Astrophys.}
\vspace{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Molecular Depletion and Thermal Balance in Dark Cloud Cores}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Paul F. Goldsmith$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {National Astronomy and Ionosphere Center,
Department of Astronomy, Cornell University, Ithaca, NY 14853, USA}\\
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: pfg@astrosun.tn.cornell.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\def\cc{cm$^{-3}$}
%% Within the following brackets you place your text:
{We analyze the effects of molecular depletion on the thermal balance of
well--shielded, quiescent dark cloud cores.
Recent observations of significant depletion of molecules from the
gas phase onto grain surfaces in dark clouds suggest the possibility
that the gas phase cooling in these regions is greatly reduced, and consequently
that gas kinetic temperatures might be increased.
We reexamine cooling and heating processes in the light
of possible molecular depletion, including the effect of coupling between
the gas and the grains.
At densities $\leq$ 10$^{3.5}$ \cc, the gas temperature can be significantly
increased by depletion of coolant species without significantly affecting
the dust temperature, due to the relatively weak dust--gas coupling.
At higher densities, this coupling becomes sufficiently rapid to overwhelm
the effect of the reduced gas--phase cooling, and depletion has little effect
on the gas temperature while raising the dust temperature $\simeq$ 1 K.
The result is that depletion at densities $\geq$ 10$^{4.5}$ \cc~ can proceed
without being evident as an enhanced gas temperature or without self--limiting
due to an increase in the dust temperature increasing the desorption rate.
This is consistent with observations of depletion in cold, dense regions of quiescent
molecular clouds.
It also suggests that depletion in moderate density regions can increase the
thermal gas pressure, effectively enhancing the confinement of denser portions
of molecular clouds and possibly accelerating the collapse of cloud cores.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ.}
%% If preprints are available on the WWW you can give the web
%% direction here.
\vspace{0.3cm}
%% Between these brackets you write the title of your paper:
{\large\bf{Disk Frequencies and Lifetimes in Young Clusters}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Karl E. Haisch Jr.$^1$, Elizabeth A. Lada$^1$ \ and Charles J. Lada$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {University of Florida, Dept. of Astronomy, 211 SSRB, Gainesville,
Florida 32611, USA} \\
$^2$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden Street,
Cambridge, Massachusetts 02138, USA} \\
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: khaisch@mail.arc.nasa.gov}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We report the results of the first sensitive {\it L}-band survey of the
intermediate age (2.5 -- 30 Myr) clusters NGC 2264, NGC 2362 and NGC 1960.
We use {\it JHKL} colors to obtain a census of the circumstellar disk
fractions in each cluster. We find disk fractions of 52\% $\pm$ 10\%,
12\% $\pm$ 4\% and 3\% $\pm$ 3\% for the three clusters respectively.
Together with our previously published {\it JHKL} investigations of the
younger NGC 2024, Trapezium, and IC 348 clusters, we have completed the
first systematic and homogenous survey for circumstellar disks in a sample
of young clusters that both span a significant range in age (0.3 -- 30 Myr)
and contain statistically significant numbers of stars whose masses span
nearly the entire stellar mass spectrum. Analysis of the combined survey
indicates that the cluster disk fraction is initially very high ($\geq$ 80\%)
and rapidly decreases with increasing cluster age, such that half the stars
within the clusters lose their disks in $$ 30 K
have been detected at 63$''$ ($\sim$0.13 pc) south from the
protostar.
It is remarkable that the blue wings in the submillimeter lines
are stronger by a factor of 3--4 than that of the CO $J$=1--0
emission line.
The CO line ratios
suggest that the blueshifted lobe of this outflow consists of
moderately dense gas of $n$(H$_2$) = (1--3)$\times$10$^{4}$
cm$^{-3}$ heated to $T_{\rm kin}$ = 50--170 K.
It is also suggested that the kinetic temperature of the outflowing gas
increases from $\sim$80 K near the protostar
to $\sim$170 K at the shocked region in the lobe center,
toward which the
largest velocity dispersion of the CO emission is observed.
A remarkable correlation between the kinetic temperature and
velocity dispersion of the CO emission along the lobe
provides us with
direct evidence that the molecular gas
at the head of the jet-driven bow shock
is indeed heated kinematically.
The lower temperature of $\sim$80 K measured at the other
shocked region near the end of the lobe
is explained if this shock is in a later
evolutionary stage, in which the gas has been cooled mainly through
radiation of the CO rotational lines.}
% Here you write which journal accepted your paper, for example:
{Accepted by ApJ }
%% If preprints are available on the WWW you can give the web
%% direction here.
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{Dense gas and cold dust in the dark core B217}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{S.~Hotzel$^1$, J.~Harju$^2$, D.~Lemke$^1$, K.~Mattila$^2$, C.\,M.~Walmsley$^3$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Max-Planck-Institut f\"ur Astronomie, K\"onigstuhl~17,
D-69117~Heidelberg, Germany} \\
$^2$ {Observatory, P.O.~Box~14,
FIN-00014 University of Helsinki, Finland} \\
$^3$ {Osservatorio Astrofisico di Arcetri, Largo~E.~Fermi~5,
I-50125 Firenze, Italy}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: hotzel@mpia-hd.mpg.de}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand{\um}{\mbox{{\usefont{U}{eur}{m}{n}\symbol{22}}m}}
\newcommand{\sforw}{\mbox{$\;\!$}} %Zwischenraum von +2/18 quad
\newcommand{\sback}{\mbox{$\!\:\!$}} %Zwischenraum von -2/18 quad
\newcommand{\tforw}{\mbox{$\:\!$}} %Zwischenraum von +1/18 quad
\newcommand{\tback}{\mbox{$\!\;\!$}} %Zwischenraum von -1/18 quad
\newcommand{\expm}[2]{\mbox{${#1}\sback\cdot\sback10^{#2}$}}
\newcommand{\expt}[2]{\mbox{{#1}$\tforw\cdot$10$^{#2}$}}
\newcommand{\NHt}{\mbox{NH$_3$}}
%\newcommand{\CeiO}{\mbox{C$\tforw^{18}\tback$O}}
\newcommand{\Htwo}{\mbox{H$_2$}}
\newcommand{\nHtwo}{\mbox{$n(\Htwo)$}}
\newcommand{\NHtwo}{\mbox{$N(\Htwo)$}}
\newcommand{\NNHt}{\mbox{$N(\NHt)$}}
\newcommand{\isos}{ISOPHOT Serendipity Survey}
\newcommand{\bsw}{B217SW}
\newcommand{\bnw}{B217NW}
\newcommand{\bne}{B217NE}
\newcommand{\oneone}{\mbox{$(J,K)=(1,1)$}}
\newcommand{\twotwo}{\mbox{$(J,K)=(2,2)$}}
\newcommand{\onetwo}{\mbox{$(J,K)=(1,1)$} and \mbox{$(2,2)$}}
%% Within the following brackets you place your text:
{The Barnard object B217 was observed in the infrared and radio region.
The 170~\um\ continuum was detected with ISOPHOT, the ammonia 1.3~cm
radio lines
with the Effelsberg 100\,m-telescope.
Mapping \bsw\ in
\onetwo\ inversion lines revealed the temperature and density
distribution of the gas and made it possible to investigate the
dynamical state of this dense core inside B217.
The \isos\ (ISOSS)
detected the cold dust emission
of B217 in all of 3 slews crossing the region.
Combining ISOSS with IRAS data, we derive the
core parameters of the dust from FIR emission and
compare them with the \NHt\ data, which sample the densest region of
the core.
This study shows the power of combining
ISOSS 170~\um\ with IRAS/HIRES data in order to study
the dust characteristics in nearby star forming regions on small
spatial scales.\newline
%
The (170\,\um/100\,\um)
dust colour temperature is 11~K--12~K in the dense cores and 12~K--14~K
in the other regions of B217.
The low dust temperatures cannot be explained
by attenuation of the interstellar radiation field
alone and may reflect a change in
the optical properties of the dust as compared to diffuse clouds.
In \bsw, molecular depletion through freeze-out onto grains is suggested
by the comparison of our FIR and \NHt\ data with previous \CeiO\
observations.
On the basis of our ammonia data investigation,
we find in \bsw\ dense gas with
kinetic temperatures between 9~K and 12~K, increasing outwards.
Using near-infrared extinction and
\NHt\ collisional excitation calculations,
the fractional ammonia abundance (\NNHt/\NHtwo) is found to be
\expt{3--5}{-8}, and
the comparison of gas and dust observations supports
this range.
Knowing the ammonia abundance, we
calculate the thermal, turbulent and gravitational energies of the
dense core, which appears to be
close to hydrostatic equilibrium.
Our results are compatible with
\bsw\ being now on the verge of
collapse or in an early collapse phase.}
% Here you write which journal accepted your paper, for example:
{Accepted by A\&A}
%% If preprints are available on the WWW you can give the web
%% direction here.
{Preprints available at \ttfamily http://www.mpia-hd.mpg.de/homes/hotzel/pubs/preprint.ps.gz}
\vspace{0.3cm}
{\large\bf{K$'$ Band Polarimetric Imaging of S187 IR and S233}}
{\bf{ Z. Jiang$^{1,2}$, Y. Yao$^{1,3}$, J. Yang$^1$, M.
Ishii$^{2,3}$, T. Nagata$^{2,3}$, H. Nakaya$^2$, S. Sato$^2$ }}
$^1$ {Purple Mountain Observatory, National Astronomical Observatories, =
Nanjing, 210008, China} \\
$^2$ {Department of Astrophysics, Faculty of Sciences, Nagoya =
University, Nagoya 464-8602, Japan} \\
$^3$ {Okayama Astrophysical Observatory of National Astronomical
Observatory, Japan} \\
{E-mail contact: zbjiang@pmo.ac.cn, jiang@z.phys.nagoya-u.ac.jp}
{K$'$ band polarimetric images of star forming regions S187 IR
and S233 are presented. In S187 IR, a bipolar near infrared
nebula is observed around IRAS 01202+6133, with the southern part
being bright and knotty, and the northern one faint and
filamentary. The polarization pattern shows that the nebula is
illuminated by a single near infrared source, which is associated
with IRAS 01202+6133. A polarization disk is found around this
source with the disk plane roughly perpendicular to the axis of
the bipolar nebula. We conclude that this source is the driving
source of the outflow in the region.
Two nebulae are detected in the S233 region. Associated with a
compact infrared cluster, S233 A is roughly round in shape and
shows a weak polarization pattern. The S233 B nebula shows roughly
elongated geometry in the E-W direction. The polarization vectors
divide it into three parts. Each part has distinctly different
polarization from the others. The NE part of S233 B exhibits a
centro-symmetric polarization pattern around a centroid, where we
locate a deeply embedded source (DES), undetected in the K$'$ band
and shorter wavelengths. The DES is likely the exciting source of
water masers and of the outflows in the S233 B region. The
western part of the nebula shows a parallel polarization pattern
but the SE part displays very little polarization.
Comparison of the morphology and polarization of the nebulae in
different star forming regions suggests a close relationship
between the evolutionary sequence of the YSOs and morphology of
the associated nebulae. }
{Accepted by Astron. J. }
Online preprint available http://jets.pmo.ac.cn
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{The T\,Tauri star RXJ\,1608.6-3922 -- not an eclipsing binary
but a spotted single star }}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{V. Joergens $^1$, E. Guenther $^2$, R. Neuh\"auser $^1$,
M. Fern\'andez $^3$ \ and J. Vijapurkar $^4$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Max-Planck-Institut f\"ur Extraterrestrische Physik,
Giessenbachstrasse 1, D-85748 Garching, Germany} \\
$^2$ {Th\"uringer Landessternwarte Tautenburg,
Karl-Schwarzschild-Observatorium, Sternwarte 5, D-07778 Tautenburg,
Germany} \\
$^3$ {Instituto de Astrof\'{\i}sica de Andaluc\'{\i}a (CSIC),
Apdo. 3004, E-18080 Granada, Spain }\\
$^4$ {Homi Bhabha Centre for Science Education
(Tata Inst. of Fundamental Research), V. N. Purav Marg
Mankhurd, Mumbai 400088, India}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: viki@mpe.mpg.de}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{High-resolution spectroscopy and photometric monitoring
of the pre-main sequence star RXJ\,1608.6-3922 shows
that it is not an eclipsing binary, as previously claimed.
Radial velocity measurements covering suitable time spans
in order to detect a spectroscopic binary with the claimed period
of about 7 days have been performed.
The scatter of the radial velocity does not exceed
2.4\,km\,s$^{-1}$, defining an upper mass limit of
24 M$_{\mbox{\tiny Jupiter}}$
for any eclipsing companion orbiting
this star with the claimed period.
Photometric observations of RXJ\,1608.6-3922 in 7 consecutive nights
(i.e. as long as the claimed orbital period)
reveal brightness variations of the order of 0.2\,mag
with a period of 3.6\,days. The shape of the detected
light curve differs from a light curve
of the star recorded in 1996.
The small variations of the radial velocity,
the variable shape of the light curve,
as well as (B-V) color variations
suggest
that the flux of RXJ\,1608.6-3922 is modulated
by spots on the stellar surface
with a rotational period of 3.6\,days.
The stellar activity of this star seems to be highly variable,
taking into account
the variable shape of the light curve, with an amplitude varying
from 0.5 to 0.2\,mag in a few years, as well as hints for
a variable H$_{\alpha}$ equivalent width.}
% Here you write which journal accepted your paper, for example:
{ Accepted by A\&A }
%% If preprints are available on the WWW you can give the web
%% direction here.
{For preprints via ftp or WWW: http://www.xray.mpe.mpg.de/$\sim$viki}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Large Area Mapping at 850 Microns.
III. Analysis of the Clump Distribution in the Orion B Molecular Cloud}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Doug Johnstone$^1$, Mike Fich$^2$, George F. Mitchell$^3$ and
Gerald Moriarty-Schieven$^4$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy, University of Toronto, Toronto,
ON, M5S 3H8, Canada}\\
$^2$ {Department of Physics, University of Waterloo, ON,
N2L 3G1, Canada}\\
$^3$ {Department of Astronomy and Physics, Saint Mary's University,
Halifax, NS, B3H 3C3, Canada}\\
$^4$ {National Research Council of Canada, Joint Astronomy Center,
660 North Aohoku Place, University Park, HI 96720, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: johnstone@astro.utoronto.ca}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
\newcommand{\etal}{{\em et al.\ }}
%% Within the following brackets you place your text:
We present results from a survey of a 900 arcmin$^2$
region of the Orion B molecular cloud, including NGC 2068, NGC 2071, and
HH 24/25/26, at 850$\mu$m using the Submillimeter Common-User Bolometer Array
(SCUBA) on the James Clerk Maxwell Telescope. Following the techniques
developed by Johnstone \etal (2000a,b), we identify 75 independent objects
and compute size, flux, and degree of central concentration. Comparison
with isothermal, pressure-confined, self-gravitating Bonnor-Ebert spheres
implies that the clumps have internal temperatures of $20 - 40\,$K
and surface pressures $5.5 < {\rm log}P/k < 6.5$. The clump masses span
$0.2 - 12.3\,M_\odot$ assuming typical dust temperatures and a dust
emissivity $\kappa_{850} = 0.01\,$cm$^{2}$g$^{-1}$. The distribution of
clump masses is well characterized by a power-law $N(M) \propto M^{-\alpha}$
with $\alpha = 1.5 - 2.0$ for $M > 1.0\,M_\odot$. Significant incompleteness
makes determination of the slope at lower masses difficult. The two-point
correlation function of the clump separations is measured revealing
clustering on size scales $r < 1.5 \times 10^5\,$AU with a radial power-law
exponent $\gamma = 0.75$.
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{
Study of star formation in RCW 106 using
far infrared observations
}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{
A.D. Karnik, S.K. Ghosh, T.N. Rengarajan \ and R.P. Verma
}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Tata Institute of Fundamental Research, Homi Bhabha Road,
Mumbai (Bombay) 400 005, India }
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: vermarp@tifr.res.in}
%% Within the following brackets you place your text:
{
High resolution far-infrared observations of a large area of the star forming
complex RCW 106 obtained using the TIFR 1m balloon-borne telescope
are presented. Intensity maps have been obtained simultaneously in two
bands centred around 150 and 210 $\mu$m. Intensity maps have also been
obtained at the four {\it IRAS} bands using HIRES processed {\it IRAS} data.
From the 150 and 210 $\mu$m maps, reliable maps of
dust temperature and optical depth have been generated.
The star formation in this complex has occurred in five
linear sub-clumps. Using the map at 210 $\mu$m, which has a spatial
resolution superior to that of the {\it IRAS} at 100 $\mu$m, 23 sources
have been identified. The spectral energy distribution (SED) and
luminosity of these sources have been determined using the associations
with the {\it IRAS} maps. Luminosity distribution of these sources has been
obtained. Assuming these embedded sources to be ZAMS stars and
using the mass-luminosity relation for these, the power law slope of
the initial mass function is found to be $-1.73\pm0.5$. This index for
this very young complex is about the same as that for more evolved
complexes and clusters. Radiation transfer calculations in
spherically symmetric geometry have been undertaken to fit the
SEDs of 13 sources with fluxes in both the TIFR and the {\it IRAS} bands.
From this, the r$^{-2}$ density distribution in the envelopes is ruled out.
Finally, a correlation is seen between the luminosity of embedded
sources and the computed dust masses of the envelopes.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by MNRAS }
%% If preprints are available on the WWW you can give the web
%% direction here.
{Preprint available at {\tt http://xxx.lanl.gov/abs/astro-ph/0104350 }}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The mean surface density of companions in a
stellar-dynamical context}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Ralf Klessen$^{1,2,3}$ \ and Pavel Kroupa$^4$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {UCO/Lick Observatory, University of California, 499 Kerr Hall,
Santa Cruz, CA 95064, USA}\\
$^2$ {Otto Hahn Fellow,
Max-Planck-Institut f{\"u}r Astronomie, K{\"o}nigstuhl 17, 69917
Heidelberg, Germany} \\
$^3$ {Sterrewacht Leiden, Postbus 9513, 2300-RA Leiden,
The Netherlands}\\
$^4$ {Institut f\"{u}r Theoretische Physik und Astrophysik,
Universit\"at
Kiel, 24098 Kiel, Germany}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: ralf@ucolick.org}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Applying the mean surface density of companions, $\Sigma(r)$, to the
dynamical evolution of star clusters is an interesting approach to
quantifying structural changes in a cluster. It has the advantage
that the entire density structure, ranging from the closest binary
separations, over the core-halo structure through to the density
distribution in moving groups that originate from clusters, can be
analysed coherently as one function of the stellar \mbox{separations
$r$}.
This contribution assesses the evolution of $\Sigma(r)$ for clusters
with different initial densities and binary populations. The changes
in the binary, cluster and halo branches as the clusters evolve are
documented using direct $N$-body calculations, and are correlated with
the cluster core and half-mass radius. The location of breaks in the
slope of $\Sigma(r)$ and the possible occurrence of a binary gap can
be used to infer dynamical cluster properties.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronomy and Astrophysics }
%% If preprints are available on the WWW you can give the web
%% direction here.
{ Preprints available at http://arxiv.org/abs/astro-ph/0103298 }
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The Formation of Stellar Clusters: Mass Spectra from Turbulent
Molecular Cloud Fragmentation}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Ralf S.\ Klessen}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{UCO/Lick Observatory, University of California at Santa Cruz,
499 Kerr Hall, Santa Cruz, CA 95064, U.S.A.}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: ralf@ucolick.org}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
Star formation is intimately linked to the dynamical evolution of
molecular clouds. Turbulent fragmentation determines where and when
protostellar cores form, and how they contract and grow in mass via
competitive accretion from the surrounding cloud material. This
process is investigated, using numerical models of self-gravitating
molecular cloud dynamics, where no turbulent support is included,
where turbulence is allowed to decay freely, and where it is
continuously replenished on large, intermediate and small scales,
respectively. Molecular cloud regions without turbulent driving
sources, or where turbulence is driven on large scales, exhibit
rapid star formation in a clustered mode, whereas interstellar
turbulence that carries most energy on small scales results in
isolated star formation with low efficiency.
The clump mass spectrum of shock-generated density fluctuations in
pure hydrodynamic, supersonic turbulence is not well fit by a power
law, and it is too steep at the high-mass end to be in agreement
with the observational data. When gravity is included in the
turbulence models, local collapse occurs, and the spectrum extends
towards larger masses as clumps merge together, a power-law
description $dN/dM \propto M^{\nu}$ becomes possible with slope $\nu
\le -2$. In the case of pure gravitational contraction, i.e.\
in regions without turbulent support, the clump mass spectrum is
shallower with $\nu \approx -3/2$.
The mass spectrum of protostellar cores in regions without turbulent
support and where turbulence is replenished on large-scales,
however, is well described by a log-normal or by multiple power
laws, similar to the stellar IMF at low and intermediate masses. The
model clusters are not massive enough to allow for comparison with
the high-mass part of the IMF. In the case of small-scale
turbulence, the core mass spectrum is too flat compared to the IMF
for all masses.
}
% Here you write which journal accepted your paper, for example:
{Accepted by ApJ }
%% If preprints are available on the WWW you can give the web
%% direction here.
A low-resolution preprint is available at astro-ph/0104127, in
full-resolution at \\
http://www.ucolick.org/$\sim$ralf/Preprints/p13.abstract.html.
\v5
{\large\bf{V $-$ (V-I) distance to Lupus 2}}
{\bf{ J. Knude and A. S. Nielsen}}
{Niels Bohr Institute for Astronomy, Geophysics and Physics, Juliane Maries Vej 30, DK-2100 K{\o}benhavn {\O}, Denmark}
{E-mail contact: indus@astro.ku.dk}
{We report a possible distance to the star forming cloud Lupus 2
of 360
pc, at least 150 pc larger than previously suggested. Despite the cloud's small
angular size and remoteness this distance estimate is corroborated by
Hipparcos/Tycho data for field stars.
The increased distance changes the mass estimate from 100 to $\sim$600
$\cal M$$_{\rm sun}$ more like the masses for the other Lupus clouds, but more
interestingly the virial ratio of the two C$^{\rm 18}$O cores in Lupus 2
will be lowered by a factor of 2.4 making Lupus 2 more like Taurus than
the remaining Lupus cores.
{ Accepted by Astron. and Astrophys. }
\vspace{0.3cm}
{\large\bf{A possible dependence of DF Tauri's photometric activity on the relative
orbital positions of the binary components}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{S.A.Lamzin$^1$, S.Yu.Melnikov$^2$, K.N.Grankin$^2$ and
O.V. Ezhkova$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Sternberg Astronomical Institute, Moscow V-234, 119899 Russia} \\
$^2$ {Ulugh Beg Astronomical Institute and
Isaac Newton Institute Uzbekistan Branch,
Astronomicheskaya 33, Tashkent 700052, Uzbekistan}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: lamzin@sai.msu.ru}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We constructed a DF~Tau historical lightcurve to analyze the character of
stellar variability from 1900 to 2000. This time interval exceeds the
orbital period $P\simeq 80$ yrs of the double system. At least two sections
of enhanced photometric activity are present at the lightcurve, with the
time interval between them being close to P/2. They correspond to the
sections of the DF~Tau companion orbit intermediate between apo- and
periastron. A decreasing in stellar activity occured near the last
periastron epoch. We conclude that long-term variations of DF Tau activity
are the result of modulation of primary circumstellar disc accretion rate by
orbital motion of the companion. We predict that DF Tau activity will
increase significantly in the near future.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. Astroph. }
%% If preprints are available on the WWW you can give the web
%% direction here.
{preprint available at ftp://lnfm1.sai.msu.ru/pub/PEOPLE/lamzin}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Hydrodynamical Simulations of Jet- and Wind-driven
Protostellar Outflows}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Chin-Fei Lee, James M. Stone, Eve C. Ostriker
\ and Lee G. Mundy }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Astronomy Department, University of Maryland, College Park, MD 20742, USA}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: chinfei@astro.umd.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
We present two-dimensional hydrodynamical simulations of
both jet- and wind-driven models for
protostellar outflows in order to make detailed comparisons
to the kinematics of observed molecular outflows.
The simulations are performed with the ZEUS-2D hydrodynamical code
using a simplified equation of state, simplified cooling and
no external heating, and no self-gravity.
In simulations of steady jets, swept-up ambient gas forms a thin shell that
can be identified as a molecular outflow. We find a simple ballistic
bow-shock model is able to reproduce the structure and transverse velocity
of the shell.
Position-velocity (PV) diagrams for the shell cut along the outflow axis
show a convex spur structure with the highest velocity at the bow tip,
and low-velocity red and blue components at any viewing
angle.
The power-law index of the mass-velocity relationship ranges
from 1.5 to 3.5, depending strongly on the inclination.
If the jet is time-variable,
the PV diagrams show multiple convex spur structures
and the power-law index becomes smaller than the steady jet
simulation.
In simulations of isothermal steady wide-angle winds, swept-up ambient gas
forms a thin shell which at {\em early} stages has a similar shape to the shell in
the jet-driven model; it becomes broader at later times.
We find the structure and kinematics of the
shell is well described by
a momentum-conserving model similar to that of Shu et al. (1991).
In contrast to the results from jet simulations, the PV diagrams for the shell
cut along the outflow axis show a lobe
structure tilted with source inclination,
with components that are primarily either red or blue unless the
inclination is nearly in the plane of sky.
The power-law index of the mass-velocity
relationship ranges from 1.3 to 1.8.
If the wind is time-variable,
the PV diagrams also show multiple structures, and the power-law index
becomes smaller than the steady wind simulation.
Comparing the different simulations with observations, we find
that some outflows, e.g., HH 212,
show features consistent with the jet-driven model, while others,
e.g., VLA 05487, are consistent with the wind-driven model.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by The Astrophysical Journal}
%% If preprints are available on the WWW you can give the web
%% direction here.
Full paper available at astro-ph/0104373
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The Bell Laboratories $^{13}$CO Survey:
Longitude-Velocity Maps}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Youngung Lee$^{1,2}$, Antony A. Stark$^2$, Hyun-Goo Kim$^1$ \ and
Dae-Sik Moon$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Korea Astronomy Observatory/Taeduk Radio Astronomy Observatory,
Whaam-dong 61-1, Yusong-gu, Taejon, 305-348, Korea} \\
$^2$ {Harvard-Smithsonian Center for Astrophysics, 60 Garden St. MS-78, Cambridge,
MA02138, USA} \\
$^3$ {Cornell University, Department of Astronomy, Ithaca, NY14853, USA }
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: yulee@trao.re.kr}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{
A survey is presented of the Galactic plane in the $J=1-0$ transition
of $^{13}$CO. About 73,000 spectra were obtained with the 7 m
telescope at Bell Laboratories over a ten-year period.
The coverage of survey is ($l, b$) =
($-5^{\circ}$ to $117^{\circ}, -1^{\circ}$ to $+1^{\circ}$),
or 244 square degrees,
with a grid spacing of $3'$ for $|b| <
0^{\circ}\!.5$, and a grid spacing of $6'$ for $|b| > 0^{\circ}\!.5$.
The data presented here have been resampled onto a $3'$ grid.
For 0.68 km s$^{-1}$ channels, the rms noise level of the survey is
0.1 K on the $T_R^*$ scale. The raw data have been transformed into FITS
format, and all the reduction processes, such as correcting for
emission in the reference positions, baseline removal and
interpolation were conducted within IRAF using the FCRAO task package
and additional programs. The reduced data are presented here in the
form of longitude-velocity color maps at each latitude. These data
allow identification and classification of molecular clouds with masses
in excess of $\sim 10^3$ solar masses throughout the first quadrant of
the Galaxy. Spiral structure is manifested by the locations of the
largest and brightest molecular clouds.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJS}
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
{\large\bf{Ring Formation in Magnetically Subcritical Clouds and Multiple Star Formation}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Zhi-Yun Li }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Department of Astronomy, University of Virginia, P.O. Box 3818,
Charlottesville, VA 22903, USA}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: zl4h@virginia.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We study numerically the ambipolar diffusion-driven evolution of
non-rotating, magnetically subcritical, disk-like molecular clouds,
assuming axisymmetry. Previous similar studies have concentrated
on the formation of single magnetically supercritical cores at the
cloud center, which collapse to form isolated stars. We show that,
for a cloud with many Jeans masses and a relatively flat mass
distribution near the center, a magnetically supercritical ring
is produced instead. The supercritical ring contains a mass well
above the Jeans limit. It is expected to break up, through both
gravitational and possibly magnetic interchange instabilities,
into a number of supercritical dense cores, whose dynamic collapse
may give rise to a burst of star formation. Non-axisymmetric
calculations are needed to follow in detail the expected ring
fragmentation into multiple cores and the subsequent core
evolution. Implications of our results on multiple star formation
in general and the northwestern cluster of protostars in the
Serpens molecular cloud core in particular are discussed.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ }
%% If preprints are available on the WWW you can give the web
%% direction here.
{preprint available at astro-ph/0105028}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{New observations of the pulsating PMS star V351~Ori}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ M. Marconi$^1$, V. Ripepi$^1$, S. Bernabei$^{2,3}$,
F. Palla$^4$, J.M. Alcal\`a$^1$, E. Covino$^1$, \, and L. Terranegra$^1$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Osservatorio Astronomico di
Capodimonte, Via Moiariello 16, I-80131 Napoli, Italy
\\
$^2$ {Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna, Italy}
\\
$^3$ {Dipartimento de Astrof\'isica, Universidad de La Laguna, Avda.
Astrofisico F. S\`anchez s/n, 30071 La Laguna, Spain}
\\
$^4$ {Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5, I-50125 Firenze,
Italy}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: marcella@na.astro.it}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{This is the abstract of your paper}
We present new precise photoelectric observations of the Pre--Main-Sequence
$\delta$ Scuti star, V351~Ori. These new data show that V351~Ori pulsates in a
mixture of several radial modes (at least four). The comparison between
observations and detailed pulsational models allows us to provide independent
constraints on the mass and luminosity of the star. The predicted distance is
210 pc, indicating that V351~Ori is much closer than the Orion star forming
region. With an inferred mass of 1.8 M$_\odot$ and an uncertain evolutionary
stage, V351~Ori represents an excellent candidate for future
asteroseismological studies that will assess whether it is a young PMS star
($\sim$6 Myr) or an evolved object ($\sim$1 Gyr) leaving the main-sequence.
% Here you write which journal accepted your paper, for example:
{ Accepted by A\&A, Letters}
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{A Submillimeter Dust and Gas Study of the Orion B Molecular Cloud}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{George F. Mitchell$^1$, Doug Johnstone$^2$,
Gerald Moriarty-Schieven$^3$, Michel Fich$^4$,and N. F. H. Tothill$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Astronomy and Physics,
Saint Mary's University, Halifax, NS, B3H 3C3, Canada}\\
$^2$ {Department of Astronomy, University of Toronto,
Toronto, ON, M5S 3H8, Canada}\\
$^3$ {Joint Astronomy Centre, 660 North A'ohoku Place,
University Park, Hilo, HI 96720, USA}\\
$^4$ {Department of Physics, University of Waterloo,
Waterloo, ON, N2L 3G1, Canada}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: gmitchell@ap.stmarys.ca}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
Using SCUBA on the JCMT, we obtained a map of 850 $\mu$m continuum
emission from the Orion B molecular cloud. The map is
20$'$ x 40$'$ in extent and covers much of the
northern half of the GMC. 67 discrete continuum sources, or clumps,
have been identified, many of which are grouped in three regions,
near NGC~2071IR, NGC~2068, and HH 24/25/26. Masses of the sources
range from 0.2 to 12 $M_{\odot}$. About half of the area of our
850 $\mu$m map is covered by the current release of the 2MASS
infrared survey. Of 40 clumps covered by the 2MASS, 14 have associated
infrared sources detected in J, H, and K.
Maps of $^{13}$CO J=2--1 and C$^{18}$O J=2--1 line emission were obtained
for two regions in order to find the gas column density.
Formaldehyde spectra were obtained towards eight of the continuum
clumps to determine the gas kinetic temperature. Three of the
clumps with measured temperature are hot ($T_{kin} \geq 80\,$K)
while the other five are cold ($T_{kin} \leq 20\,$K).
The gas-to-dust ratios differ substantially between the
two regions mapped in CO. In the NGC~2068 region we find close to
constant ratios of dust to gas emission, except in one compact source.
However in the HH 24/25/26 region the dust to gas emission ratio varies substantially with some of the brightest dust continuum
sources almost absent in CO emission. One explanation is that CO molecules
have frozen onto grains in the dense cores. Why this freeze-out
should happen in the HH 24/25/26 cores but not in the NGC~2068 cores
remains unexplained.
A $^{12}$CO J=3--2 map of the NGC~2068 region shows patches of
high velocity gas associated with five of the compact continuum sources.
The presence of outflows provides strong evidence that the
group of sources south of NGC~2068 is actively forming stars.
% Here you write which journal accepted your paper, for example:
{ Accepted by Ap. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{A SCUBA survey of the NGC~2068/2071 protoclusters}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ F. Motte$^{1,2}$, P. Andr\'e$^{3}$, D. Ward-Thompson$^{4}$,
S. Bontemps$^{5}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Max-Planck-Institut f\"ur Radioastronomie, Auf dem H\"ugel 69,
53121 Bonn, Germany} \\
$^2$ {Present address: California Institute of Technology, MS 320-47,
Pasadena, CA 91125, USA} \\
$^3$ {CEA, DSM, DAPNIA, Service d'Astrophysique, C.E. Saclay, 91191
Gif-sur-Yvette Cedex, France} \\
$^4$ {Department of Physics \& Astronomy, University of Cardiff,
P.O. Box 913, Cardiff, UK} \\
$^5$ {Observatoire de Bordeaux, BP 89, 33270 Floirac, France}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: motte@submm.caltech.edu}
%% Within the following brackets you place your text:
{
We report the results of a submillimeter dust continuum survey of the
protoclusters NGC~2068 and NGC~2071 in Orion~B carried out at
$850\:\mu$m and $450\:\mu$m with SCUBA on JCMT. The mapped region is
$\sim 32' \times 18'$ in size ($\sim 4$~pc~$\times$~2~pc) and consists
of filamentary dense cores which break up into small-scale ($\sim
5\,000$~AU) fragments, including 70 starless condensations and 5
circumstellar envelopes/disks. The starless condensations, seen on
the same spatial scales as protostellar envelopes, are likely to be
gravitationally bound and pre-stellar in nature. Their mass spectrum,
ranging from $\sim 0.3~M_\odot$ to $\sim 5~M_\odot$, is reminiscent of
the stellar initial mass function (IMF). Their mass-size relation
suggests that they originate from gravitationally-driven
fragmentation. We thus argue that pre-collapse cloud fragmentation
plays a major role in shaping the IMF.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. \& Astrophys. Letter}
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprint available at
http://www.submm.caltech.edu/\~motte/papers.html\#ngc2068 (965 Kb,
PS-gzipped)\\
or http://xxx.lanl.gov/abs/astro-ph/0105019
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{
Measurement and Interpretation of Deuterium Line Emission in the
Orion Nebula}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
%{\bf{ First Author$^1$, Second Author$^2$ \ and Third Author$^3$ }}
{\bf{C. R. O'Dell$^1$, G. J. Ferland$^2$ \ and W. J. Henney$^3$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Department of Physics and Astronomy, Vanderbilt University, Nashville, TN, USA} \\
$^2$ {Department of Physics and Astronomy, University of Kentucky, Lexington, KY, USA} \\
$^3$ {Instituto de Astronom\'{\i}a, UNAM Campus Morelia, Morelia, Michoac\'an, Mexico}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: cr.odell@vanderbilt.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We present new observations of the deuterium and hydrogen Balmer lines in the
Orion Nebula. There is a real variation in the ratio of the deuterium to hydrogen
line ratios across the nebula, being greatest in the emission from the largest
proplyd (Orion 244-440). We also present the results of a detailed model for
the emission of these lines, the hydrogen lines being the result of photoionization
and recombination, while the deuterium lines are produced by fluorescent excitation
of the upper energy states by the far-UV radiation from $\theta^1$~Ori~C. Comparison
of the observations and predictions of the line intensities shows good agreement,
both in the strength of the reference lines at H$\beta$ and also in the differences
of the Balmer decrement for the two atoms.
The fact that both the deuterium and hydrogen emission arise from mechanisms
which count the near ultra-violet (deuterium) and photo-ionizing ultra-violet
(hydrogen) photons from the dominant star means that there is little prospect of similar
observations being useful for determination of D/H abundances in H~II regions.}
% Here you write which journal accepted your paper, for example:
{ Accepted by the Astrophysical Journal}
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprints can be obtained by anonymous ftp server at orion.phy.vanderbilt.edu
within the directory pub/outgoing/Deuterium where it is the file preprint.ps.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{A ballistic bow shock model for jet-driven protostellar outflow shells}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Eve C. Ostriker, Chin-Fei Lee, James M. Stone,
and Lee G. Mundy}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Department of Astronomy, University of Maryland, College Park, MD 20742-2421}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: ostriker@astro.umd.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{ We analyze the dynamics of the shell produced when a bow shock from
a collimated jet propagates into the surrounding medium. Under
interstellar conditions, the shock is radiative, and a ballistic
approximation for the shell flow is appropriate beyond the working
surface where the jet impacts its surroundings. The solution is
then determined by the ambient and jet densities and velocities and
by the momentum impulse applied in the working surface. Using
estimates for these impulses (confirmed by separate numerical
simulations), we obtain solutions for the shell structure, and for
the range of velocities in the shell at any point. We provide
predictions for the position-velocity and mass-velocity relations
expected for plane-of-sky bow-shock shells, and for the bulk shell
properties. In a companion paper, we show that these analytic
solutions are in excellent agreement with the results of direct
numerical simulations. We argue that classical molecular (CO)
outflows cannot be purely jet-driven, because the bow-shock shell
solutions are much too elongated compared with observations.
Finally, we suggest that the ``spur'' structures seen in
position-velocity diagrams of observed molecular outflows are the
manifestation of internal bow shocks which may be fit with our simple
dynamical models.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by The Astrophysical Journal}
%% If preprints are available on the WWW you can give the web
%% direction here.
Full paper available at astro-ph/0104374.
%\end{document}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Gas phase production of NHD$_2$ in L134N}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{S. D. Rodgers and S. B. Charnley }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{Space Science Division, MS 245-3, NASA Ames Research Center,
Moffett Field, CA 94035, U.S.A.}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: rodgers@dusty.arc.nasa.gov}
%% If you use any personal Latex commands in your abstract, please include
%% their definitions here.
%% Within the following brackets you place your text:
{We show analytically that large abundances of NH$_2$D and NHD$_2$ can
be produced by gas phase chemistry in the interiors of cold dense
clouds. The calculated fractionation ratios are in good agreement
with the values that have been previously determined in L134N and
suggest that triply-deuterated ammonia could be detectable in dark
clouds. Grain surface reactions may lead to similar NH$_2$D and NHD$_2$
enhancements but, we argue, are unlikely to contribute to the
deuteration observed in L134N.}
% Here you write which journal accepted your paper, for example:
{Accepted by ApJ (vol 553) }
%% If preprints are available on the WWW you can give the web
%% direction here.
{http://xxx.lanl.gov/abs/astro-ph/0104415}
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{VLA Observations of Brightness Enhancements moving along the Axis of the Cep A HW2 Thermal Jet}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{L. F. Rodr\'\i guez$^1$, J. M. Torrelles$^2$,
G. Anglada$^3$, and J. Mart\'\i$^4$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Instituto de Astronom\'\i a, UNAM, Campus Morelia,
Apdo. Postal 3-72, Morelia, Michoac\'an 58089, M\'exico} \\
$^2$ {Institut d'Estudis Espacials de Catalunya (IEEC/CSIC) and
Instituto de Ciencias del Espacio (CSIC),
Edifici Nexus, c/ Gran Capit\`a
2-4, E-08034 Barcelona, Spain} \\
$^3$ {Instituto de Astrof\'\i sica de Andaluc\'\i a, CSIC,
Camino Bajo de Hu\'etor 24, E-18008 Granada, Spain} \\
$^4$ {Departamento de F\'\i sica (EPS), Universidad de Ja\'en,
Virgen de la Cabeza, 2, E-23071 Ja\'en, Spain}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: luisfr@astrosmo.unam.mx}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We analyze sensitive, high angular resolution
(0$\rlap.{''}$3) Very Large Array observations
made at 6-cm of the thermal jet Cep~A~HW2
in two epochs separated by 1.3 years. The subtraction of the
maps made at the two epochs clearly shows the presence of
brightness enhancements that travel in the jet at
a velocity of 950$\pm$150 km s$^{-1}$.
We also use these results to estimate an accurate position
for the exciting star of this jet.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Revista Mexicana de Astronom\'\i a y Astrof\'\i sica}
%% If preprints are available on the WWW you can give the web
%% direction here.
http://www.astrosmo.unam.mx/\~{}luisfr/publ.html
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The Tokyo-Onsala-ESO-Cal\'an Galactic CO $J=2-1$ Survey.\\
I. The Galactic Center Region}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{
Tsuyoshi Sawada$^{1,2}$, Tetsuo Hasegawa$^{1,2}$, Toshihiro Handa$^{1}$,
Jun-Ichi Morino$^{1,3,4}$, Tomoharu Oka$^{1,5,6}$, Roy Booth$^{7}$,
Leonardo Bronfman$^{8}$, Masahiko Hayashi$^{4}$,
Abraham Luna Castellanos$^{8,9}$, Lars-{\AA}ke Nyman$^{7,10}$,
Seiichi Sakamoto$^{1,3}$, Masumichi Seta$^{1,11}$,
Peter Shaver$^{12}$, Kazuo Sorai$^{1,3,13}$ \ and
Kumiko Sato Usuda$^{1,4}$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Institute of Astronomy, University of Tokyo,
2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan} \\
$^2$ {National Astronomical Observatory of Japan,
2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan} \\
$^3$ {Nobeyama Radio Observatory,
Nobeyama, Minamimaki, Minamisaku, Nagano 384-1305, Japan}\\
$^4$ {Subaru Telescope, 650 North A'ohoku Place, Hilo, Hawaii 96720}\\
$^5$ {Faculty of Science, University of Tokyo,
7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0013, Japan}\\
$^6$ {Institute of Physical and Chemical Research (RIKEN),
2-1 Hirosawa, Wako, Saitama 351-0198, Japan}\\
$^7$ {Onsala Space Observatory, S-439 92 Onsala, Sweden}\\
$^8$ {Departamento de Astronom\'{\i}a, Universidad de Chile,
Casilla 36-D, Santiago, Chile}\\
$^9$ {Instituto Nacional de Astrof\'{\i}sica \'Optica Y Electr\'onica,
Tonantzintla Puebla, Mexico}\\
$^{10}$ {Swedish-ESO Submillimetre Telescope,
Casilla 19001, Santiago 19, Chile}\\
$^{11}$ {Communications Research Laboratory,
4-2-1 Nukuikita, Koganei, Tokyo 184-8795, Japan}\\
$^{12}$ {European Southern Observatory, Karl-Schwarzschild-Stra{\ss}e 2,
D-85748 Garching bei M\"unchen, Germany}\\
$^{13}$ {Division of Physics, Graduate School of Science,
Hokkaido University, Sapporo 060-0810, Japan}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: sawada.tsuyoshi@nao.ac.jp}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{As a part of the Tokyo-Onsala-ESO-Cal\'an Galactic ${\rm CO}$ survey,
we have made large-scale mapping observations of the Galactic center
in the ${\rm CO}\; J=2-1$ line using the 60{\,}cm survey telescope
in Chile.
The data were taken with the same beam size ($9^\prime$) and sampling
grid ($7.5^\prime$) as the ${\rm CO}\; J=1-0$ Columbia survey,
so that the two datasets can be compared directly.
Velocity channel maps and longitude-velocity diagrams of the
${}^{12}{\rm CO}\; J=2-1$ line covering
$-6^\circ \le \ell \le +6^\circ $,
$-2^\circ \le b \le +2^\circ $,
$-300\,{\rm km\, s^{-1}} \le v_{\rm LSR} \le +300\,{\rm km\, s^{-1}}$
are presented along with the corresponding maps of the
${}^{12}{\rm CO}$ $J=2-1/J=1-0$ intensity ratio
($R_{2-1/1-0}({}^{12}{\rm CO})$).
A longitude-velocity diagram of the
${}^{13}{\rm CO}\; J=2-1$ line intensity and corresponding
${}^{13}{\rm CO}\; J=2-1/{}^{12}{\rm CO} \; J=2-1$ intensity ratio
($R_{13/12}(J=2-1)$) are also presented at $b = 0^\circ $.
%
The overall $R_{2-1/1-0}({}^{12}{\rm CO})$ in the central
$900\,{\rm pc}$ of the Galaxy is
$0.96\pm 0.01$, which is higher than the typical value
in the Galactic disk, $0.6$-$0.7$.
The isotopic intensity ratio $R_{13/12}(J=2-1)$ is $0.10\pm 0.01$.
The observed two intensity ratios ($R_{2-1/1-0}({}^{12}{\rm CO})$ and
$R_{13/12}(J=2-1)$) indicate
that the optical depth of the ${}^{12}{\rm CO}\; J=1-0$ line is
$\sim 1$ or smaller in the Galactic center molecular clouds, much smaller
than those of the giant molecular clouds (GMCs) in the Galactic disk.
%
Longitude-velocity distributions of physical properties of molecular gas
are derived using an LVG analysis.
Molecular gas in the Galactic center generally shows a high pressure.
Particularly, there is a high pressure region in the central
$\sim 100\,{\rm pc}$ where the pressure is an order of magnitude higher
than that in GMCs in the Galactic disk.
This region is dominated by high density gas and contains
star forming regions.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astrophys. J. Suppl. }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{Comparative seismology of pre- and main
sequence stars}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ Marian Suran$^1$, MarieJo Goupil$^2$, Annie
Baglin$^3$, Yveline Lebreton$^2$ \ and Claude Catala$^4$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Astronomical Institute of Romanian Academy} \\
$^2$ {DASGAL, UMR CNRS 8633, Observatoire de Paris-Meudon, France} \\
$^3$ {DESPA, UMR CNRS 8632, Observatoire de Paris-Meudon, France} \\
$^4$ {LAOMP, UMR CNRS 5572, Observatoire Midi-Pyr\'en\'ees, France}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: suran@roastro.astro.ro}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Pulsational properties of
1.8 M$_{\odot }$ stellar models
covering the latest stages of contraction toward the main
sequence up to early hydrogen burning phases
are investigated by means of linear nonadiabatic analyses.
Results confirm that pre-main sequence stars (pms) which cross the
classical
instability strip on their way toward the main sequence are
pulsationally unstable with respect to the
classical opacity mechanisms.
For both pms and main sequence types of models in the lower part of
the instability
strip, the unstable frequency range is found to be roughly the
same. Some non-radial unstable modes are very
sensitive to the deep internal structure of the star.
It is shown that discrimination between
pms and main sequence stages
is possible using differences in their oscillation frequency
distributions
in the low frequency range.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astronnomy \& Astrophysics}
%% If preprints are available on the WWW you can give the web
%% direction here.
\clearpage
%% Between these brackets you write the title of your paper:
{\large\bf{The Probability Distribution Function of Column Density in
Molecular Clouds}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Enrique V\'azquez-Semadeni$^1$ and Nieves Garc\'ia$^2$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Instituto de Astronom\'\i a, UNAM, Campus Morelia,
Apdo. Postal 3-72, Xangari, 58089, Morelia, Mich., Mexico} \\
$^2$ {nstituto de Astronom\'\i a, UNAM, Apdo. Postal 70-264,
M\'exico D.F., 04510, Mexico}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: e.vazquez@astrosmo.unam.mx}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We discuss the probability distribution function (PDF) of column
density resulting from density fields with lognormal PDFs, applicable
to isothermal gas (e.g., probably molecular clouds). For magnetic and
non-magnetic numerical simulations
of compressible, isothermal turbulence forced at intermediate scales
(1/4 of the box size), we find that the autocorrelation
function (ACF) of the density field decays over relatively short
distances compared to the simulation size. We suggest that a
``decorrelation length'' can be defined as the distance over which the
density ACF has decayed to, for example, 10\% of its zero-lag value, so
that the density ``events'' along a line of sight can be assumed
to be independent over distances larger than this, and the
Central Limit Theorem should be applicable. However, using random
realizations of lognormal fields, we show that
the convergence to a Gaussian is extremely slow in the high-density tail.
As a consequence, the column density PDF is not expected to
exhibit a unique functional shape, but to transit
instead from a lognormal to a Gaussian form as the ratio $\eta$ of the
column length to the decorrelation length (i.e., the number of
independent events in the cloud) increases. Simultaneously, the PDF's
variance decreases.
For intermediate values of $\eta$, the column density PDF assumes
a nearly exponential decay. For cases with a density
contrast of $10^4$ (resp.\ $10^6$), as found in intermediate-resolution
simulations, and expected from GMCs to dense molecular cores,
the required value of $\eta$ for convergence to a Gaussian is at least a
few hundred (resp.\
several thousand). We then discuss the density power spectrum and the
expected value of $\eta$ in actual molecular clouds, concluding that they
are uncertain since they may depend on several physical parameters.
Observationally, our results suggest that $\eta$ may be inferred from the
shape and width of the column density PDF in optically-thin-line or
extinction studies. Our results should also hold for gas with
finite-extent power-law underlying density PDFs, which should be
characteristic of the diffuse, non-isothermal neutral medium (temperatures
ranging from a few hundred to a few thousand degrees). Finally, we note
that for $\eta \geq 100$, the dynamic range in column density is small
($\leq$ a factor of 10), but this is only an averaging effect, with
no implication on the dynamic range of the underlying density
distribution.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ }
%% If preprints are available on the WWW you can give the web
%% direction here.
Preprints available at astro-ph/0103199. Note that the paper has been replaced
since its first posting there, with significant changes.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{
Submillimeter CO Line Emission from Orion } }
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf { T. L. Wilson$^{1}$ ,$^{2}$,
D. Muders$^{1}$,$^{2}$, C. Kramer$^{3}$,
C. Henkel$^{2}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1${Sub-Millimeter Telescope Observatory, Steward Observatory,
The University of Arizona, Tucson, Az., 85721 USA}\\
$^{2}${Max Planck Institut f\"{u}r Radioastronomie, Postfach 2024,
D-53010 Bonn, Germany}\\
$^{3}${I. Physikalisches Inst., Univ. zu K\"oln, Z\"ulpicherstr.
77, D-50937 K\"oln, Germany}
}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: twilson@as.arizona.edu, dmuders@mpifr-bonn.mpg.de, }
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{Images of an 8 square minute region around the Orion KL source have
been made in the $J=7-6$ (806 GHz) and $J=4-3$ (461 GHz) lines of CO
with angular resolutions of 13$''$ and 18$''$. These data were taken
employing on-the-fly mapping and position switching techniques. Our $J=7-6$ data set is the largest image of Orion with the highest
sensitivity and resolution obtained so far in this line.
Most of the extended emission arises from a Photon Dominated Region (PDR), but 8\% is associated with the Orion ridge. For the prominent Orion KL outflow, we produced ratios of the integrated intensities of our $J=7-6$ and
$4-3$ data to the $J=2-1$ line of CO. Large Velocity Gradient (LVG)
models fit the outflow ratios better than PDR models. The LVG models give
H$_2$ densities of $\sim$10$^5$ cm$^{-3}$. The CO outflow is probably heated by shocks. The data for Orion~S suggest that this source is located {\it inside} the HII region, near the rear of Orion A. In the Orion~S outflow, the CO line intensities are lower than for Orion~KL. The $4-3$/$2-1$ line ratio is 1.3 for the blue shifted wing and 0.8 for the red shifted wing. Emission in the jet feature extending 2$'$ to the SW of Orion~S was detected in the $J=4-3$ but not the $J=7-6$ line; the average $4-3$/$2-1$ line ratio is $\sim$1. Comparisons of the intensities of the $J=7-6$ and $J=4-3$ lines from the Orion Bar with PDR models show that the ratios exceed predictions by a factor of 2. Either clumping or additional heating by mechanisms, such as shocks, may be the cause of this discrepancy.}
% Here you write which journal accepted your paper, for example:
{ Accepted by the Astrophysical Journal }
%% If preprints are available on the WWW you can give the web
%% direction here.
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{The formation of heavy hydrocarbons in molecular clouds}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{Ararat G. Yeghikyan$^{1,2}$, Serena Viti$^2$ and David A.
Williams$^2$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Byurakan Astrophysical Observatory, 378433 Byurakan, Republic of
Armenia} \\
$^2$ {Department of Physics and Astronomy, University College
London, London WC1E 6BT, UK }
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: sv@star.ucl.ac.uk}
%% Within the following brackets you place your text:
{Laboratory data on the conversion of solid methane into large
hydrocarbons by particle radiation are used to estimate the fraction of
interstellar carbon converted by this process into refractory form. We
find that the maximum fraction of carbon that can be converted into
refractory form during the life of a dense core within an interstellar
cloud is in the range of 1 - 5 percent. The implication of this result is
that the conversion of enough carbon into refractory form to contribute
significantly to interstellar extinction requires the frequent passage of
material into and out of dense cores. If so, then interstellar clouds must
exist for at least 10 My. However, these conclusions should be regarded
as preliminary until confirmed by further laboratory studies of the
particle irradiation of complex ice mixtures.}
% Here you write which journal accepted your paper
{Accepted by MNRAS }
\v5
%% Between these brackets you write the title of your paper:
{\large\bf{A Subarcsecond Radio Binary Associated with
AFGL~4029-IRS1}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{L. A. Zapata$^{1,2}$ L. F. Rodr\'\i guez$^1$, and S. E. Kurtz$^1$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {Instituto de Astronom\'\i a, UNAM, Campus Morelia,
Apdo. Postal 3-72, Morelia, Michoac\'an 58089, M\'exico} \\
$^2$ {Escuela de Matem\'aticas, Universidad Aut\'onoma
de Coahuila, Edificio D, Unidad Camporredondo, Saltillo, Coahuila 25000,
M\'exico}
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc, for example:
{E-mail contact: luisfr@astrosmo.unam.mx}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{We present sensitive, high angular resolution
(0$\rlap.{''}$3) Very Large Array observations
made at 3.6-cm of the bright infrared source
AFGL~4029. We find that the radio source
G138.295+1.555, associated with AFGL~4029-IRS1,
is actually a subarcsecond binary
separated by 0$\rlap.{''}$6 approximately in the north-south direction.
There is also fainter emission extending in the east-west direction
and emanating from G138.295+1.555(S), the southern component of the binary.
We then identify G138.295+1.555(S) as the exciting source of the optical
and molecular outflow observed in this region. G138.295+1.555(S) appears
to be one of the few massive young stars associated with a collimated outflow.
The northern component of the binary,
G138.295+1.555(N), appears to exhibit time-variable radio
emission and is proposed to be associated with a T Tauri star.
The source G138.300+1.558,
associated with AFGL~4029-IRS2, is an ultracompact H~II region
of cometary morphology, possibly ionized by a B1 ZAMS star.
}
% Here you write which journal accepted your paper, for example:
{ Accepted by Revista Mexicana de Astronom\'\i a y Astrof\'\i sica}
%% If preprints are available on the WWW you can give the web
%% direction here.
http://www.astrosmo.unam.mx/\~{}luisfr/publ.html
\v5
%% Between these brackets you write the title of your paper:
{\large\bf Search for CO Outflows toward a Sample of 69 High-Mass Protostellar Candidates: Frequency of Occurrence}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf {Qizhou Zhang$^{1}$, T. R. Hunter$^{1}$, J. Brand$^{2}$, T. K. Sridharan$^{1}$, S. Molinari$^{3}$, M. Kramer$^{4}$ and R. Cesaroni$^{5}$}}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
{$^{1}$Harvard Smithsonian Center for Astrophysics,
60 Garden Street,
Cambridge, Massachusetts 02138, USA\\}
{$^{2}$Istituto di Radioastronomia, C.N.R.
Via Gobetti 101
I-40129 Bologna, Italy\\}
{$^{3}$Istituto di Fisica Spazio Interplanetario - CNR
Via Fosso del Cavaliere, I-00133,
Roma, Italy \\ }
{$^{4}$Oberlin College, Mailroom Box 1634, Oberlin, Ohio 44074, USA \\}
{$^{5}$Osservatorio Astrofisico di Arcetri,
Largo E. Fermi 5, I-50125 Firenze, Italy }
%% Here you may write the e-mail address of one or more of the authors
%% who will act as contact person for preprint requests etc., for example:
{E-mail contact: qzhang@cfa.harvard.edu.
%% Within the following brackets you place your text:
{A survey for molecular outflows was carried out by mapping the CO J=2-1 line
toward a sample of 69 luminous IRAS point sources. 60 objects have
IRAS luminosities from
$10^3$ to $10^5$ ${\rm L_\odot}$ and are associated with dense gas
traced by ${\rm NH_3}$,
identifying them as high-mass star forming regions.
Among 69 sources, 65 sources have data that are suitable for outflow
identification. 39 regions show spatially confined
high velocity wing emission in CO, indicative of
molecular outflows. Most objects
without identifiable outflows lie within $0 < l < 50^\circ$ where
outflow signatures are confused by multiple cloud components along
the line of sight. Excluding
26 sources with $0 < l < 50^\circ$,
we found 35 outflows out of 39 sources, which yields an outflow
detection rate of 90\%.
Many of the outflows contain masses of more than 10 ${\rm M_\odot}$ and have
momenta of a few
hundred ${\rm M_\odot~km~s^{-1}}$, at least two orders of magnitude larger than those in
typical low-mass outflows. This class of massive and energetic
outflows are most likely driven by high-mass young stellar objects.
The high detection rate indicates that molecular
outflows are common toward high-mass young stars.
Given the connection between outflows and accretion disks in
low-mass stars, we suggest that
high-mass stars may form via an accretion-outflow process, similar to
their low-mass counterparts.}
% Here you write which journal accepted your paper, for example:
{ Accepted by ApJ Letters }
Preprint: {http://cfa-www.harvard.edu/$^\sim$qzhang or
http://cfa-www.harvard.edu/sfgroup}
\vspace{2cm}
\fboxrule0.02cm
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\fbox{\rule[-0.9cm]{0.0cm}{1.8cm}{\parbox{16cm}
{The Star Formation Newsletter is a vehicle for fast distribution of
information of
interest for astronomers working on star formation and molecular
clouds. You can submit material for the following sections: {\em
Abstracts of recently accepted papers} (only for papers sent to refereed
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(presenting abstracts of new Ph.D dissertations), {\em Meetings}
(announcing meetings broadly of interest to the star formation
and interstellar medium community), {\em New Books} (giving details of
books relevant for the same community), {\em New Jobs} (advertising
jobs specifically aimed towards persons within our specialty), and {\em
Short Announcements} (where you can inform or request information from
the community). \\
{\bf Latex macros for submitting abstracts and dissertation abstracts
are appended to each issue of the newsletter}. \\
The Star Formation Newsletter is available on the World Wide Web at
http://casa.colorado.edu/reipurth or at
http://www.eso.org/gen-fac/pubs/starform/ .
}}}
\vspace{2cm}
\begin{center}
\fboxrule0.02cm
\fboxsep0.4cm
\fbox{\rule[-0.9cm]{0.0cm}{1.8cm}{\parbox{11cm}
{ {\Large\bf Moving ... ??}\\
If you move or your e-mail address changes, please send the editor your
new address. If the Newsletter bounces back from an address for three
consecutive months, the address is deleted from the mailing list.
}}}
\end{center}
\newpage
\begin{center}
{\Large\em Dissertation Abstracts}
%\end{center}
%% Between these brackets you write the title of your thesis:
{\Large\bf{Physical Properties of Protostars}}
\vspace*{0.5cm}
%% Here comes your name
{\bf{ Markus Nielbock }}
%% Here you write the institute where your thesis work was conducted, e.g.:
{Thesis work conducted at: Astronomisches Institut der Ruhr-Universit\"at
Bochum, Germany}
%% Here comes your present postal address (if you are about to move and know
%% your coming address give it as well) e.g.:
{Current address: Astronomisches Institut der Ruhr-Universit\"at Bochum,
Universit\"tsstr. 150, D-44780 Bochum, Germany}
%% (if you use this part, remove %%)
%% {Address as of XX XXX 1994: }
%% Here comes your e-mail address:
{Electronic mail: nielbock@astro.ruhr-uni-bochum.de}
%% Name of your adviser:
{Ph.D dissertation directed by: Prof. Dr. Rolf Chini}
%% Month and Year of thesis:
{Ph.D degree awarded: May 2001}
\vspace*{0.8cm}
\end{center}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%\newcommand{\micron}{\,$\mu$m}
\newcommand{\sqmin}{\scriptsize$\Box$\normalsize$'$}
\newcommand{\famin}{$'\hspace{-2.6pt}.$}
\newcommand{\ion}[2]{#1~\textsc{#2}}
%% Within the following brackets you place your text:
Prominent star forming regions have been investigated at wavelengths between
1.2\micron\ to 1300\micron, covering a large mass spectrum of the observed
young stellar objects. Their evolutionary stages were determined by established
classification procedures and turned out to range from collapsing cloud
fragments, Class~0 protostars to more evolved Class~I sources. The creation
of spectral energy distributions allowed to derive physical properties like
temperatures, luminosities, masses and densities by fitting modified
Planck functions to the measured flux distributions. For source extents that
exceed the expected size of a pointsource, their dimensions have been obtained
by two-dimensional Gaussian fits. In cases, where measurements from different
epochs exist, a possible temporal evolution has been discussed.
\medskip
The study of low-mass objects has been carried out in dark molecular clouds,
widely spread throughout the galactical plane,
where Herbig--Haro objects are a signpost of star formation activity.
7 of 17 observed sources are Class~0 protostars, with HH~108~MMS being
one of the youngest stellar objects discovered so far. 5 additional
objects appear to be in a transitional stage between Class~0 and Class~I.
A surprising result of this study was the detection of Herbig--Haro objects
at (sub)millimetre wavelengths which could originate from warm dust, compressed
by the associated molecular outflows or jets.
\medskip
The bright emission nebula M~17 (Omega nebula, NGC~6618) has been chosen as
a template for high-mass star formation, where the investigations were
concentrated on the adjacent molecular cloud M~17~SW. In order to examine the
warm extended dust, mid-infrared maps, created from 133 single images at
10.5\micron\ and 20.0\micron\, covering $\sim$17 sqmin, have been produced. An
eye-catching dust ridge of 4\famin5 length and a colour temperature of 230~K
has been found which most probably consists of dense dust, swept up by an
advancing ionization front. The mosaic shows 22 compact sources which have
been investigated in more detail; 4 are new detections. All sources satisfy
the Class~I criterion; 4 of them lie close to the Class~II borderline. The
observed objects comprise a binary
of massive young stars, one of those being a quickly evolving ultra-compact
\ion{H}{ii} region, massive Class~I sources surrounded by dust cocoons and
circumstellar disks, and probably the first detection of a protostellar
spiral.
%% If you have your thesis on the web, please provide the web address here
http://www.astro.ruhr-uni-bochum.de/nielbock/promotion/
\end{document}
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%%% LaTeX MACRO FOR THE STAR FORMATION NEWSLETTER %%%
%%% %%%
%%% Please use for abstracts of papers which have been ACCEPTED in %%%
%%% REFEREED JOURNALS (do not send abstracts of reviews for books %%%
%%% or conference notes). Merely fill in the brackets below and %%%
%%% mail to reipurth@casa.colorado.edu. If you have problems, let %%%
&&& me know in an accompanying note and I will fix them. %%%
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%\begin{document}
%% Between these brackets you write the title of your paper:
{\large\bf{Title of Paper}}
%% Here comes the author(s) of the paper, please indicate within $^...$
%% the number which corresponds to the institute of each author.
{\bf{ First Author$^1$, Second Author$^2$ \ and Third Author$^3$ }}
%% Here you write your institute name(s) and address(es),
%% the number in $^..$ indicates your author number, for example:
$^1$ {European Southern Observatory, Casilla 19001, Santiago 19, Chile} \\
$^2$ {Cerro Tololo Inter-American Observatory, National Optical Astronomy
Observatories, Casilla 603, La Serena, Chile} \\
$^3$ {Las Campanas Observatory, Carnegie Inst. of Washington, Casilla
601, La Serena, Chile}
%% Here you may write the e-mail address of one or more
%% of the authors who will act as contact person for
%% preprint requests etc., for example:
{E-mail contact: astronomer@star.institute.edu}
%% IF YOU USE ANY PERSONAL LATEX COMMANDS IN YOUR ABSTRACT,
%% PLEASE INCLUDE THEIR DEFINITIONS HERE!
%% Within the following brackets you place your text:
{This is the abstract of your paper.}
% Here you write which journal accepted your paper, for example:
{ Accepted by Astron. J. }
%% If preprints are available on the WWW you can give the web
%% direction here.
%\end{document}
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%%%
%%% LaTeX MACRO FOR DISSERTATION ABSTRACTS
%%%
%%% Please use the following macro for your thesis abstract. You
%%% have one full page for everything, and you are very welcome to
%%% go into detail with your results, so the readers get a
%%% comprehensive overview of your work. Merely fill in the
%%% brackets below and mail to reipurth@casa.colorado.edu
%%%
%%%
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% To process with latex, first remove the % in front of latex commands
%\documentclass[]{article}
%\textwidth 18cm
%\textheight 23cm
%\oddsidemargin -1cm
%\topmargin 0cm
%\parskip 0.15cm
%\parindent 0pt
%\small
%\begin{document}
\begin{center}
%% Between these brackets you write the title of your thesis:
{\Large\bf{Title of Thesis}}
\vspace*{0.5cm}
%% Here comes your name
{\bf{ Author }}
%% Here you write the institute where your thesis work was conducted, e.g.:
{Thesis work conducted at: Steward Observatory, University of Arizona, USA}
%% Here comes your present postal address (if you are about to move and know
%% your coming address give it as well) e.g.:
{Current address: European Southern Observatory, Casilla 19001,
Santiago 19, Chile}
%% (if you use this part, remove %%)
%% {Address as of XX XXX 1994: }
%% Here comes your e-mail address:
{Electronic mail: doctor@sun.institute.edu}
%% Name of your adviser:
{Ph.D dissertation directed by: Galileo Galilei}
%% Month and Year of thesis:
{Ph.D degree awarded: Month Year}
\vspace*{0.8cm}
\end{center}
%% Within the following brackets you place your text:
{This is the abstract of your thesis}
%\end{document}